The following chart shows the thickness of most used paper stocks in printing industry.
To calculate the  total thickness of your printing project, please find the number of pages of your project and use the below formula to calculate the thickness of your printing project:  
Thickness of your printing project = (Paper thickness) x ( Number of pages) / 2. For example if your are designing a 120 pages book on 100# gloss book the thickness of this book is:  (120x0.005") / 2 = 0.3".

Un-coated / Offset Opaque Paper Stocks

Approx. Caliper / Thickness

50lb Offset Text Uncoated paper 0.0035"
60lb Offset Text Uncoated paper 0.004"
70lb Offset Text Uncoated paper 0.005"
80lb Offset Text Uncoated Paper 0.0055"
100lb Opaque Text Uncoated Paper 0.007"
65lb Opaque Cover Uncoated Paper 0.009"
80lb Opaque Cover Uncoated Paper 0.011" (11pt Thick)
100lb Opaque Cover Uncoated Paper 0.014" (14pt Thick)

Gloss Coated Paper Stocks

 Approx. Caliper / Thickness

70lb Gloss Book coated paper 0.0035"
80lb Gloss Book coated paper 0.004"
100lb Gloss Book coated paper 0.005"
80lb Gloss Cover Coated paper 0.0075" (7.5pt)
100lb Gloss Cover Coated paper 0.0092" (9pt)

Satin / Dull Coated Paper Stocks

Approx. Caliper / Thickness

70lb Satin or Dull Book coated paper 0.0038"
80lb Satin or Dull Book coated paper 0.0045"
100lb Satin or Dull Book coated paper 0.0055"
80lb Satin or Dull Cover Coated paper 0.0081" (8pt)
100lb Satin or Dull Cover Coated paper 0.011" (11pt)